code: def create_mock_df(freq="Q-DEC"):
      df2 = pd.DataFrame(
          pd.date_range(start="1/1/2010", periods=31, freq=freq),
          columns=["time_col"],
      )
      df3 = df2.copy()
  
      df2["target_col"] = range(1, 32)
      df2["group_col"] = "a"
      df2["group_col_2"] = "a2"
      df2["group_col_3"] = "a3"
  
      df3["target_col"] = range(11, 42)
      df3["group_col"] = "b"
      df3["group_col_2"] = "b2"
      df3["group_col_3"] = "b3"
  
      return pd.concat([df2, df3]).reset_index(drop=True)
  
file_path: mindsdb/tests/unit/ml_handlers/test_time_series_utils.py
imports: import pandas
  from statsforecast.utils import AirPassengersDF
  from mindsdb.integrations.utilities.time_series_utils import transform_to_nixtla_df, get_results_from_nixtla_df, infer_frequency, get_best_model_from_results_df, spec_hierarchy_from_list, get_hierarchy_from_df, reconcile_forecasts
label_desc: Use image node_id 1 for calling a global function with example usage: create_mock_df(freq) and returns: pd